Kivonat:
Cytogenetic aberrations are very important factors in risk
assessment of childhood hematological malignancies. We report
six childhood acute lymphoid leukemia (ALL) cases with rare
cytogenetic aberrations: five with RUNX1, ABL1 or MLL proto-
oncogene amplification and one case of multiple copies of
ETV6/RUNX1 fusion genes. The simultaneous presence of two
adverse genetic aberrations is of special interest: ETV6-RUNX1
fusion gene is associated with good prognosis and
intrachromosomal amplification of the homologue RUNX1 gene is
associated with poor prognosis. We also report a patient with
MLL amplification, a unique finding in childhood T-ALL. Report
of these subtle rearrangements contributes to our understanding
of diagnostic and prognostic significance of these rare
cytogenetic abnormalities.